pooling.h

/* Copyright (c) 2016 Baidu, Inc. All Rights Reserved.
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==============================================================================*/

#pragma once

#include "common/log.h"
#include "framework/tensor.h"

namespace paddle_mobile {
namespace operators {
namespace math {

#define FLT_MAX __FLT_MAX__

/*
 * \brief Extracting simple operations from pooling.
 *        Both MaxPool and AvgPool need "initial", "compute" and "finalize"
 * operation.
 *        MaxPool initializes temp variable to the negative maximum to find the
 * maximum value in the pooling field.
 *        AvgPool initializes temp variable to the zero to accumulate all values
 * in pool pooling, and finally takes the average.
 *        MaxPoolGrad and AvgPoolGrad are gradient operations respectively.
 */
template <class T> class MaxPool {
public:
  inline T initial() { return static_cast<T>(-FLT_MAX); }

  inline void compute(const T &x, T *y) { *y = *y > x ? *y : x; }

  inline void finalize(const T &pool_field, T *y) {}
};

template <class T> class AvgPool {
public:
  inline T initial() { return static_cast<T>(0); }

  inline void compute(const T &x, T *y) { *y += x; }

  inline void finalize(const T &pool_field, T *y) { *y /= pool_field; }
};

template <typename DeviceType, typename PoolProcess, typename T>
class PoolFunctor {
public:
  void operator()(const framework::Tensor &input, const std::vector<int> &ksize,
                  const std::vector<int> &strides,
                  const std::vector<int> &paddings, PoolProcess pool_compute,
                  framework::Tensor *output);
};
}
} // namespace operators
} // namespace paddle_mobile